Manhole cover



1 June 23, 1925. 1,542,900

A. MADDOCKS MANHOLE COVER Filed Feb. 4. 1924 r-"w I /3 I 8 l/ W m g :1 %\wlhifl mum g Hi 4 5 A gvvuwntoz flnfiur Naddocks.

' tion.

Patented June 23, 1925.

U Ismr Anr a-MAnnocns, or DENVER, conoaeno.

' I Me anoma YoovER.

Application filed 'iehruar'y 4, I924. Serial 1rd. 690,485.

and State of Colorado, have invented cer tain new and useful Improvements in Manhole Covers, and I do declare the following to be a full, clear, and exact descrip-' tlon of the lnventlon, such as will enable others skilled in "the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the characters of reference markedthereon, which form apart'of this specifica- This invention relates to improvements lliIllEtIlhOlE covers andhas special reference tom'eans for locking the same in piece.

' Tn'ou r cities there area largenumber of sewers, tunnels and conduits of various k nds, to whlch accessishad through-man holes. The manholes are located in'the alleys and streets and are "closed by strong cast-iron covers that rest on a flange secured to a ring. It frequently happens that the covers are removed either accidentally orintentionally, with the result that serious accidents happen. Owing to the suction between the surface of the roadway and a pneumatic automobile tire, it sometimes happens that the covers are removed from manholes by any rapidly passing automobile that may pass over them.

It is the object of this invention to produce a simple locking means, with which 7 any manhole cover can be equipped, and

which will positively prevent the cover from becoming accidental removed.

f Manholes are usually round openings with sides of brick or concrete, to the top of which is secured a cast-iron ring having an inwardly extendlng flange upon whlch the cover rests. My invention, briefly described,

consists in providing the cover with a lug that will engage the under side of the flange, and which cooperates with a turn button secured to the cover at a point diametrically opposite to the lug. When the cover is in place and the turn button moved into such a position that it will project under t-he flange, the cover will be locked against removal. I also provide means which will hold the turn button from accidental rotation and which cannotbe put into place until the turn button is in looking position My invention can be mQstly clearly dc;

Fig. 5.

scribed and will be most readily understood when reference" isjhad to the accompanying drawing, in which the preferred embodiment thereof is illustrated, and in which:

Fig. I is a plan view of the top oif a manhole withthe cover in place thereon, a portion of the'cover being broken awayto show the flange, i

Fig; 2 is 'ajseetion taken on line 2+2, Fig. 1 and shows the coverfi'n locked positiOT-l; V 5 V.

Fig. 3 is aysection similar to that-shown in Fig. 2, butwith the parts shown on an enlarged scale 'Fig. 4 is a plan view 'o f a portion of the, cover shown 7 in 'Fig. I '3 Fig. 5' is a bottom plan view of the lock- 7 ing plug and Fig. 6 is a section taken on '-li-ne 6.'6,

Numeral 1 Y represents the cast-iron ring that is secured to the top of the Imanhole "wall. This ring has an inwardly projecting flange 2 upon which the cover 3 is supported. A lug 4: is secured to the underside of the'cover by means of rivets 5. The end 6 of this lug is offset to such an extent that the space between it and the under side of the cover will receive the flange 2 in the manner shown in Figs. 2 and 3. Near the edge of the cover diametrically opposite from the lug 4, I drill a hole 7 and a larger hole 8 which intersects the hole 7 in the manner shown infFig. 4:. Underneath holes 7 and 8 I secure a plate 9 by means of rivets 10. Plate 9 is slightly thicker than the flange 2 and has an opening substantially centrally located with respect to the hole 8. A spindle 110 is rotatably mounted in the opening in plate 9. This spindle has a noncircular head 11 that projects into the hole 8. The head 11 is unsymmetrical with respect to one axis so that it will entera correspondingly shaped hole in one way only. Non-rotatably secured to the outer end of spindle 110 is a turn button 12 which is of greater length than width so that it will, when in one position, project beyond plate 9 and engage the under side of flange 2 in locked in place. I contemplate providing a socket wrench by means of which the head 11 may be engaged for rotating the spindle and the turn button, although this can, under ordinary circumstances, be accomplished by means of a pair of pliers. For the purpose of filling the opening 7 and 8 and for positively holding the turn button in looking position, I provide a plug 13 whose outer periphery is shaped to conform to theopening 7 and 8. On its lower side plug 13 has an opening 14: shaped to receive the head 11. As the plug canonly be inserted into the opening in the cover in one way and as the head 11 will enter opening 14 in only one way, and since the opening 14 is so arranged with respect to the plug and the head 11 that the plug can only be put into place when the turn button is in looking position, it is evident that after the plug has been put into place, the cover cannot be unlocked without first removing the plug, thereby assuring that the cover cannot accidentally become unlocked. The upper side of the cover is provided with two depressions separated by a wall 15 that can be grasped by the fingers or by a pair of pliers, when the plug is to be removed.

From the above, it is evident that'I have produced a simple means that can be cheaply applied to any existing cover, and which will positively hold the same against accidental removal. Of course the locking means described, does not prevent a mischievous person, provided with the necessary tools, from removing the cover, but the labor required to remove the same is sufficient to deter any ordinary person from removing the cover, and as the lock is a positive preventive of accidental removal, the danger of accidents the side opposite from the lug, a plate secured to the underside of the .cover and adapted to cover the opening, a turn button rotatably secured to said plate, means comprising'a noncircular head secured to the turn button and accessible from the top-of the plate for rotating the turn button, and

means comprising a plug having an opening adapted to receive the head for holding said button-turning means against accidental movement when the button is in locking po* sition.

In testimony whereof Iaffix my signature. 7 ARTHUR MADDOCKS. 

